The Chinese government has issued a nationwide alert in a bid to control a virus that has caused the deaths of 22 children.

The Health Ministry says the move followed a "relatively large" outbreak of enterovirus 71 (EV-71), a type of hand, foot, and mouth disease, in the central city of Fuyang.

The ministry said in a notice on its website that health bureaus around the country have been ordered to step up monitoring for the EV-71 virus, requiring all cases to be reported within 24 hours.It warned that cases were more numerous this year than in recent years and that the peak for transmission would likely come in June and July.

Hand, foot, and mouth disease is highly contagious and is spread through direct contact with the mucus, saliva, or feces of an infected person. It typically strikes small children and in some cases can cause fatal brain swelling.

Health Ministry expert Li Shuang Jie encouraged parents of sick children to wash and disinfect their hands to stop spreading the virus. Speaking on state television on May 2, Li said the symptoms of the virus were easy to miss on adults and warned that many of the adults who were in close contact with sick children could pass it on to children unknowingly.

Since early March, the virus has caused the deaths of 22 children in Fuyang, a fast-growing city surrounded by farmland in Anhui Province. Up to May 1, more than 3,300 cases of the virus were reported and nearly 980 people remain hospitalized, 58 of them in serious or critical condition.

Cases of hand, foot, and mouth outbreaks, but not necessarily EV-71, have been reported in at least two other provinces. The death of an 18-month-old boy on May 2 suggested the virus causing the illness had spread to the south.

The outbreak is another concern for the Chinese government ahead of the Beijing Olympics in August. The communist regime is also dealing with unrest in Tibetan areas that has led to international condemnation of the country's human rights record.

The outbreak is also a reminder of the SARS pneumonia outbreak in 2003, which China was blamed for covering up when it first emerged. The disease infected more than 8,000 people in nearly 30 countries and killed more than 750.